INTRODUCTION AND OBJECTIVES: Chronic spontaneous urticaria (CSU) has a substantial impact on patient health-related quality of life (HRQoL). This study aims to document published utility values associated with CSU health states and derive new CSU health-state utility scores using recent randomized clinical trial (RCT) data.
MATERIALS AND METHODS: A systematic literature review (SLR) was conducted from 1 January 2013 to 31 May 2023 utilizing Embase, MEDLINE, EconLit, Cochrane Library, NHS EED, and ScHARRHUD databases. Additionally, scientific conference proceedings (e.g., EADV, EAACI) and key international health agency websites (e.g., NICE, EMA) were searched from 2021 through 2023. Pooled EQ-5D-5L utility data from two phase III RCTs (REMIX 1 and 2; NCT05030311 and NCT05032157) were analysed using descriptive statistics, mixed models, generalized linear mixed models for sensitivity analysis, and the UK value set recommended in the latest NICE guidance. CSU health states were defined using the weekly Urticaria Activity Score (UAS7): severe (28 to 42), moderate (16 to <28), mild (<6 to <16), well-controlled (>0 to 6), and urticaria free (0). Statistical models were developed using data at follow-up (weeks 12 and 24) as the dependent variable, and covariates for baseline utility, weight, angioedema, baseline ISS weekly itch score, sex, and UAS7 category. Marginal means with 95% confidence intervals (CIs) were estimated by health state, independent of treatment arm.
RESULTS: A total of 554 publications were retrieved; 25 studies were included. Of these, 16 were utility studies (15 real-world evidence studies; 1 RCT) and 9 were economic evaluations. Of the 16 primary utility studies, 14 reported mean utility values, 1 reported the convergent validity between UAS7 and utility, and 1 reported utility differences between CSU and psoriasis groups but not mean utility values. Values based on CSU severity were derived in 4 utility studies; the results suggested that utility score increases (i.e., improves) with decreased disease activity (Table 1). Four studies compared utility values for patients with CSU with those of controls; patients with CSU had lower scores. Two studies reported utility values among patients with CSU compared with other skin conditions (psoriasis, atopic dermatitis) and found lower values for CSU. Finally, 4 studies presented utility values for patients who were refractory or inadequately controlled by current CSU treatment. In addition, 5 economic evaluations reported utility estimates. Mean utility analysis from the REMIX trials showed that patients on remibrutinib had higher utilities than placebo at both weeks 12 and 24 despite lower utility of remibrutinib at baseline vs. placebo (Figure 1). Statistical analysis of the REMIX 1 and 2 data derived mean (95% CI) utility values of 0.749 (0.727-0.770) for severe, 0.833 (0.815-0.853) for moderate, 0.866 (0.851-0.880) for mild, 0.889 (0.871-0.906) for well-controlled, and 0.928 (0.913-0.943) for urticaria-free health states. Sensitivity analysis confirmed the robustness of the results.
CONCLUSION: The utility studies identified in the SLR and the statistical analysis of the REMIX trial data indicated that patients with CSU have lower utility values compared with healthy individuals, with greater CSU severity being associated with lower scores. Moreover, the mean utility analysis indicates the potential benefit of remibrutinib in improving patients’ HRQoL over placebo.
